Tighten WebCRT command audit: reject device errors and stdout replay.

Only audit interactive commands from frontend audit_line with a CLI prompt prefix; skip prompt-sync Enter and device error echoes; join wrapped xterm rows for long commands.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/webcrt_channel.py

@@ -539,14 +539,49 @@ def _is_prompt_command_line(line: str) -> bool:
     )
 
 
+def _has_cli_prompt_prefix(line: str) -> bool:
+    s = normalize_audit_line(line)
+    return bool(
+        re.match(
+            r"^(?:"
+            r"[\w.-]+(?:\([^)]+\))*[#>]"
+            r"|>[\w.-]+"
+            r"|<[^>]+>"
+            r"|\[[^\]]+\]"
+            r")",
+            s,
+            flags=re.I,
+        )
+    )
+
+
+def _is_device_output_line(line: str) -> bool:
+    """Device error/warning echo — never an operator-typed command."""
+    s = normalize_audit_line(line).strip()
+    if not s:
+        return False
+    low = s.lower()
+    if low.startswith("%error") or low.startswith("%warning"):
+        return True
+    if "invalid input detected" in low:
+        return True
+    if re.match(r"^\^+\s*$", s):
+        return True
+    if re.match(r"^enter configuration commands", low):
+        return True
+    return False
+
+
 def is_auditable_command_line(line: str) -> bool:
-    """False for empty Enter (prompt only, no command text)."""
+    """False for empty Enter, device output, or lines without a CLI prompt prefix."""
     s = normalize_audit_line(line)
     if not s.strip():
         return False
     if _is_prompt_only_line(s):
         return False
-    return True
+    if _is_device_output_line(s):
+        return False
+    return _has_cli_prompt_prefix(s)
 
 
 def _is_prompt_only_line(line: str) -> bool:

netx_api/webcrt_router.py

@@ -801,7 +801,10 @@ async def websocket_session(websocket: WebSocket, session_id: str) -> None:
     if sess.needs_live_prompt:
         sess.needs_live_prompt = False
         try:
-            await asyncio.get_running_loop().run_in_executor(webcrt_io_executor(), sess.write_stdin, "\r")
+            await asyncio.get_running_loop().run_in_executor(
+                webcrt_io_executor(),
+                lambda: sess.write_stdin("\r", audit_source="prompt_sync"),
+            )
         except Exception:
             _log.debug("webcrt live prompt sync failed session=%s", session_id, exc_info=True)
     try:

netx_api/webcrt_session_model.py

@@ -385,28 +385,26 @@ class WebcrtSession:
             if redacted and (buf_lines or audit_line):
                 self._password_mode = False
             if "\r" in text or "\n" in text:
-                from .webcrt_channel import (
-                    extract_last_prompt_command,
-                    is_auditable_command_line,
-                    normalize_audit_line,
-                )
+                from .webcrt_channel import is_auditable_command_line, normalize_audit_line
 
-                # Ground truth: xterm visible row at Enter (frontend). PTY stdout/stdin
-                # still carry intermediate backspaces / tab redraws — do not prefer those.
+                src = str(source or "stdin")
                 cmd: str | None = None
-                if audit_line and str(audit_line).strip():
+                if redacted and (audit_line or buf_lines):
+                    lines = ["***"]
+                elif src == "prompt_sync":
+                    lines = []
+                elif audit_line and str(audit_line).strip():
                     candidate = normalize_audit_line(audit_line)
                     if is_auditable_command_line(candidate):
                         cmd = candidate
-                if not cmd:
-                    raw = extract_last_prompt_command(self._stdout_tail)
-                    if raw and is_auditable_command_line(raw):
-                        cmd = raw
-                    elif buf_lines and str(buf_lines[-1]).strip():
-                        last = str(buf_lines[-1]).strip()
-                        if is_auditable_command_line(last):
-                            cmd = last
-                lines = [cmd] if cmd else []
+                    lines = [cmd] if cmd else []
+                elif src == "post_login":
+                    if buf_lines and str(buf_lines[-1]).strip():
+                        cmd = str(buf_lines[-1]).strip()
+                    lines = [cmd] if cmd else []
+                else:
+                    # Interactive WebCRT: only trust frontend audit_line at Enter.
+                    lines = []
                 self._last_prompt_line = ""
             else:
                 lines = []